/* 
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using Lucene.Net.Analysis.Tokenattributes;

namespace Lucene.Net.Analysis
{
    
    /// <summary>Normalizes token text to lower case.</summary>
    public sealed class LowerCaseFilter:TokenFilter
    {
        public LowerCaseFilter(TokenStream @in)
            : base(@in)
        {
            termAtt = AddAttribute<ITermAttribute>();
        }
        
        private readonly ITermAttribute termAtt;
        
        public override bool IncrementToken()
        {
            if (input.IncrementToken())
            {
                
                char[] buffer = termAtt.TermBuffer();
                int length = termAtt.TermLength();
                for (int i = 0; i < length; i++)
                    buffer[i] = System.Char.ToLower(buffer[i]);
                
                return true;
            }
            return false;
        }
    }
}